Hi Toyin,
if you are connecting to a laptop you should be using a cross-over cable
Check this reference:
http://en.wikipedia.org/wiki/Ethernet_crossover_cable
as
In the other two cases, (2950 and 3750) you should be using a straight through cable.
These ports in the 2514 support 10/half duplex. If you fix this at both sides, you should get connectivity.
In regards to Cisco cables there are plenty of places. Just google for "cisco cables"!
Regards.
Hector